1. Field of the Invention
This invention relates to an improved liftable furnace roof for an electric arc furnace in which its refractory tile members are mounted in a suspended relation from its metal structure and particularly, to a dual ring structure that enables an improved application of cooling fluid to higher temperature portions of the roof. A phase of the invention deals with a roof which carries its own exhaust hood and enables the introduction of ambient air into the hood out-flow chamber.
2. Description of the Prior Art
As pointed out in my co-pending application Ser. No. 584,631 of June 6, 1975, now U.S. Pat. No. 3,967,048 difficulties have heretofore been encountered in providing and maintaining roof constructions for electric arc furnaces. This is particularly true in view of the fact that the roof has to be tilted about 45.degree. for the furnace tapping operation and is to be lifted and swung, and utilized with electrodes during the operation of the furnace. In my co-pending application I have disclosed a roof construction which makes an effective and practicable utilization of refractory tile or block members in a so-called sprung type of roof relationship by minimizing compression thrust loading. To meet the demand for even longer roof life from the standpoint of its tile members, particularly for larger diameter roofs, e.g., twenty-two or more feet in diameter, there is a need for a so-called suspended type of roof of minimum weight which may fully utilize basic brick that normally do not have the strength for utilization in a sprung roof construction, and which will enable the use and efficient cooling of hanger castings and other supporting metal work.